FIGURE 2.

The l-galactose pathway of ascorbic acid biosynthesis is conserved in green algae. Colored squares indicate the number of A. thaliana orthologs present in each organism. The enzymes catalyzing the successive steps are hexokinase (HXK), phosphoglucose isomerase (PGI), phosphomannose isomerase (PIM), phosphomannomutase (PMM), GDP-l-mannose pyrophosphorylase (VTC1), GDP-d-mannose-3′,5′-epimerase (GME), GDP-l-galactose phosphorylase (VTC2), l-galactose-1-P phosphatase (VTC4), l-Gal-DH, and GLDH.